Comment by ptnpzwqd

Responses seem to be very "either or" as usual on such topics.

I think it should be possible to appreciate how impressive this is on one hand, while also discussing the limitations of the approach.

Everyone can probably agree that getting this far without LLMs would have taken substantially longer and required a huge amount of work.

But what is then the end result?

Personally, for me it would still be hard pass on using a 1M LoC LLM-migrated language runtime - I have seen CC do enough crazy things to still be wary of any code without a human in the loop. It simply plays too fundamental a role in the tech stack. Others might feel differently, and time will tell how things play out.

Even if this does play out as optimistically as one can imagine, would it then mean I can go and migrate some of my enterprise codebases the same way? I doubt it.

Bun has the nice feature that it has an extensive set of black box / E2E tests that don't themselves need migrating. Most projects in the wild seem to be much more reliant on unit and integration tests that are part of the codebase itself, and would therefore also need to be migrated and be subject to mistakes in the migration process.

It also seems fairly rare that test suites are good enough to guarantee that the program will work as expected in all cases. I am yet to come across a larger enterprise codebase where the tests were good enough to make human review and even manual testing fully redundant. To be honest I doubt that is the case for Bun either, but I don't know enough about bun to conclude that.